Definition: You are given a math word problem and you are supposed to make use of mathematical concepts like probability, combinatorics, linear equations, sequences/series, or simple operators like addition, subtraction, division, or multiplication to answer the given question. Choose the best option from the 5 given options and report that option.
Input: Question: If 7<x<9<y<15, then what is the greatest possible positive integer difference of x and y?

 Option A: 7

 Option B: 4

 Option C: 5

 Option D: 6

 Option E: 3

Option A